var chart1; // globally available
$(document).ready(function() {

      chart1 = new Highcharts.Chart({
         chart: {
            renderTo: 'homeGraph',
            zoomType: 'x',
            spacingRight: 20
         },
         title: {
            text: 'Visualisez votre évolution mensuelle'
         },
         xAxis: {
            categories: ['Sep. 2011', 'Oct. 2011', 'Nov. 2011', 'Dec. 2011']
         },
         yAxis: {
            title: {
               text: 'Points'
            }
         },
         legend: {
             enabled: false
         },
         series: [{
            name: 'Votre évolution',
            data: [1215, 1175, 1240, 1360]
         }]
      });
   });